Process of manufacturing available phosphoric acid.



JAMES H. CONNOR, OF NASHVILLE, TENNESSEE.

PROCESS OF MANUFACTURING AVAILABLE PHOSPHORIC ACID.

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No Drawing.

Specification of Letters Patent.

Application filed October 21, 1911. Serial No. 655,964.

Patented Oct. 29,1912.

To all whom it may concern.-

Be it known that I, JAMES H. CONNOR, a resident of Nashville, in the county of Davidson and State of Tennessee, have invented a new and useful Improvement in Processes of Manufacturing Available Phosphoric Acid, of which the following is a specification.

This invention relates to the treatment of phosphate rock, phosphate earth, phosphate pebbles, bone phosphate, lime and bones, and other phosphatic material, for the purpose of converting the insoluble phosphates con:- tained therein. into soluble phosphates, and thereby making the same available as fertilizers.

The invention is particularly applicable to the treatment of phosphate rock and other phosphatic materials which contain sandy matter or dirt and more or less alkali earths, and which for that reason have here tofore been unmarketable and unsalable. The invention, however, is applicable to the treatment of phosphatic materials of. any kind. I

The object of the invention is to provide for the treatment of such phosphatic materials, and particularly low-grade phos phate rocks and pebbles, ina manner to convert the insoluble phosphates therein into soluble and therefore available phosphoric acid, Without the use of sulfuric acid, and at a comparatively low cost.

In carrying out the process the phosphate rock or other phosphatic material as it comes out of the ground and while in its crude state, and without washing or clean ing, is first dried and then ground, crushed or pulverized to such size that all portions thereof will be acted upon in the subsequent treatment thereof. The size to which it is reduced may vary, but it has been found that a size such as to pass through a sieve of meshes to the inch gives excellent results. The ground, crushed or pulverized phosphatic material is then mixed with large percentage of the phosphoric acid into.

' citrate soluble form. Thesulfate of soda on account of its lower cost, soda ash re- 1 places a portion of the sodium sulfate. The

proportion of sodium salts to be added to the crushed phosphatic material depends upon the character of the phosphatic material and the quantity of phosphoric acid contained therein and which is to be rendered available. Good commercial results have been obtained by using 200 pounds of soda ash and 100 pounds of sulfate of soda for each 1400 pounds of phosphatic material. combination yields ap roximatel This 14 per .cent. of phosphoric aci whichis citrate soluble and about 5 per cent. which is water soluble. The proportions may, however, be

varied if agreater percentage of the phosphoric acid is to be water soluble, the sul- .fate of soda going as high as 400 pounds for each 1400 pounds of phosphatic material, with a corresponding diminution of the ;soda ash. Onthe other hand, the soda ash gmay be as high as 300 pounds for each 1400 pounds of phosphatic material with a corresponding diminution of sodium sulfate.

;The mixture is then subjected to a comparatively high temperature for from about .forty minutes to one hour, the temperature avarying from 1.700 to 3400 degrees Fahrenheit.

The higher the temperature the ishorter the time of roasting. Any form of furnace or kiln may be used for roasting the material, but it is preferred to use an ordinary rotary kilnon account of being thereby enabled to maintain a steady and uniform heat, and also because the action l of the kiln keeps the material in fairly small lumps or globules, thereby insuring the thorough roasting of the mass throughout.

The mixture can be blown into the kiln in a dry form, but preferably it is treated in a wet state by adding water thereto in sufficient quantities to convert the mixture to the consistency of thick mud, the ingredients being thoroughly mixed after the water is added to convert the same into a uniform mass of substantially the consistency stated. This not only insures a thorough intermingling or more uniform mixture or distribution of the sodium carbonate and socrushed phosphatic material,- as a result of which the action ofthe re-agent is not only rendered more rapld but also produces a larger percentage of available phosphoric acid.

In the treatment of the wet mass in the kiln the wet material does not immediately disintegrate but remains in masses of greater or less size. This has a tendency to hold the volatile elements, such as the carbon monoxid and the carbon dioxid, in the mass and prevents their too rapid escape and therefore insures the thorough action of the sodium sulfate and sodium carbonate on the phosphates and particularly prevents the excessive volatilization of the sodium component. At the same time the action of the rotary kiln breaks the mass into lumps of sufliciently small size so that the entire mass is thoroughly roasted.

A small quantity of oxid of iron, preferably fiue dust, may be added, or substituted for a part of the sodium sulfate. The quantity of flue dust may vary from 25 to pounds for each 1400pounds of phosphatic material. It causes the mixture to fuse very rapidly, producing an energetic reaction and renders the phosphoric acid water soluble.

The application of a heat of the temperature specified and continued for substantially the time specified results in separating the phosphoric acid and rendering the same soluble and available. The result is a rather concentrated product very rich in available phosphoric acid which is sufficiently separate and soluble to render the product available as a fertilizer.

The'roasted mass comes out of the kiln in the form of small lumps somewhat resembling' clinker. This is then ground, crushed or pulverized to such fineness as is desirable for fertilizing purposes, preferably to an impalpable powder or flour, and is then packed and ready for market without further treatment.

By means of the process described it, is possible to form a high grade fertilizer, rich in available phosphoric acid, from cheap phosphatic rock, earth, pebbles and the like,

which is found in large quantities in va-' rious parts of the country, mixedzwith va-t rious impurities, such as alkali earths,

which have not heretofore been available-for fertilizing purposes on account of the cost of known processes for treating the same to render the phosphoric acid available, and which processes although expensive resulted in producing only a very indifferent fertiltilferrflfom such impure phosphate rocks and What I claim is: f Y I 1. The method of treating phosphatic material in order to render the insoluble phosphates available, consisting in reducing the phosphatic material to substantially a size to pass through a sieve o-fsixty meshes to the inch, adding thereto. 100 to 400 pounds of sulfate of sodium for each 1400 pounds of phosphatic material, and subjecting the mixture to a temperature of from 1700 to 3400 degrees Fahrenheit for such length of time that the phosphoric acid becomessoluble. 4

2. The method of treating phosphatic ma- .terial in order to render the insoluble phosphates available, consisting in reducing the phosphatic material to substantially a size to pass through a sieve of sixty meshes to the inch, adding thereto sulfate of sodium and sodium carbonate, and subjecting the mixture to a temperature of from 1700 to .3400 degrees Fahrenheit for such length of time that v the phosphoric acid becomes soluble.

3. The method of treating phosphatic material in order to render the insoluble phosphates available, consistin in reducing the phosphatic material to su stantially a size to pass through a sieve of sixty meshes to the-inch, adding thereto sulfate of s'odium and carbonate of sodium in substantially the proportions of 100 pounds and upward of sulfate of sodium and 200 pounds and upward of carbonate of sodium to each 1400 pounds of phosphatic material, and then subjecting tha mixture to a fusing temperature for such length of time that the phosphoric acid becomes soluble.

4., The method of treating phosphatic mater'ial in order torender the insoluble phosphates available, consisting in reducing the phosphatic material to substantially a size to pass through a sieve of sixty meshes to the inch, adding thereto-sulfate of sodium and carbonate of sodium in substantially the proportions of100 pounds and upward of sulfate of sodium and 200 pounds and up ward of carbonate of sodium to each 1400 pounds of phosphatic material, and Water suflicient to reduce the mass to the consistency of thickmud, and subjecting the mass to atem rature of from 1700 to 3400 detopass through a sieve of'sixty meshes to the inch, adding thereto sulfate of sodium and oxid ofiron, and subjecting the mixture toa tem grees Fa renheit for such length of time that the phosphoric acid becomes soluble.

6. The method of treating phosphatic ma.-

rature of from 1700 to 3400 de-' terial in order to render the insoluble phoslength of time that the phosphoric acid bephates available, consisting in reducing the comes soluble. 10 phosphatic material to substantially a size In testimony whereof, I have hereunto set to pass through a sieve of sixty meshes to my hand.

5 the inch, adding thereto sulfate of sodium, JAMES H. CONNOR.

sodium carbonate, and oxid of iron, and sub- Witnesses: jecting the mixture to a temperature of from F. N. WINTER,

1700 to 3400 degrees Fahrenheit for such MARY E. OAHQON. 

